Write Tests

[knothed]

Write tests for the following libraries:

• Geometry. Testing includes the various Shape.contains, Shape.distance(to:), Line.distance(to:) and Line.intersection(with:) methods. PolarCoordinates should also be tested.
• ImageAnalysisKit. All image-unspecific algorithms like SmallestCircle, ConnectedChunks etc. should be tested. This also includes PixelPaths. Image-specific algorithms like EdgeDetection, RayShooter or Image.follow(path:...) should also be tested by creating testing images, for example via BitmapCanvas.
• (Optional: GameKit. Trackers could be tested by providing example data.)
• (Optional: MacTestingTools. It would be nice-to-have to test BitmapCanvas by creating example bitmaps and comparing them with expected outputs.)

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Structure:

Because tests are library-specific, it would be best to create a "Tests" directory inside each tested library (at the same level where "Sources" is).

[knothed]

Also, some things of ImageAnalysisKit were not used and not really tested until now. For example, special cases of EdgeDetector, e.g. using the inverse flag were not tested, so this should be done ASAP.